Case Based Reasoning (CBR) is more suitable for the following problems:

The problem domain is complex and not amenable to complete mathematical modeling.

An explicit model is extremely difficult to elicit and represent with rules.

Historical data exists within the organization.

The domain experts have considerable difficulty in writing down the decision rules. But, they are comfortable in providing well-proven heuristics and experiences, to incorporate into the case base as cases. They have little difficulty in recalling concrete cases, which they have encountered in the past.

The domain is such that it needs reasoning for the system's solutions.